The present invention relates to a data transmission station of the type suited for use in data transmission systems which include a unidirectional bus arranged in a ring topology.
A variety of data transmission systems have in the past used buses arranged in a ring topology. Ambriose, U.S. Pat. No. 4,539,678, Champlin, U.S. Pat. No. 4,561,088, and Blahut, U.S. Pat. No. 3,781,478, provide three examples of such data transmission systems. In the Blahut system, a negative going framing pulse 200 (FIG. 2) is used for timing purposes and is passed from terminal to terminal. Similarly, the Champlin device utilizes a framing pulse 29 to synchronize the respective terminals.
The present invention is directed to an improved data transmission station which is extremely simple to implement and is readily adaptable to data transmission systems which extend over considerable distances.